package spring;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;


/**
 * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicaitonContext. 
 * @author E440
 *	须在 spring.xml 配置文件中配置：
 *	!-- 用于持有ApplicationContext,可以使用SpringContextHolder.getBean('xxxx')的静态方法得到spring bean对象 -->  
 *	<domain class="utility.spring.SpringContextHolder" lazy-init="false" />
 */
public class SpringContextHolder implements ApplicationContextAware {  
	private static ApplicationContext applicationContext;  
	  
	/** 
	* 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量. 
	*/  
	public void setApplicationContext(ApplicationContext applicationContext) {  
		SpringContextHolder.applicationContext = applicationContext; // NOSONAR  
	}  
	  
	/** 
	* 取得存储在静态变量中的ApplicationContext. 
	*/  
	public static ApplicationContext getApplicationContext() {  
		checkApplicationContext();  
		return applicationContext;  
	}  
	  
	/** 
	* 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
	*/  
	@SuppressWarnings("unchecked")  
	public static <T> T getBean(String name) {  
		checkApplicationContext();  
		return (T) applicationContext.getBean(name);  
	}  
	  
	/** 
	* 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
	*/  
	@SuppressWarnings("unchecked")  
	public static <T> T getBean(Class<T> clazz) {  
		checkApplicationContext();  
		return (T) applicationContext.getBean(clazz);  
	}  
	  
	
	
	/** 
	* 清除applicationContext静态变量. 
	*/  
	public static void cleanApplicationContext() {  
		applicationContext = null;  
	}  
	  
	private static void checkApplicationContext() {  
		if (applicationContext == null) {  
			throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");  
		}  
	}  
} 
